fmlm is an acronym/abbreviation for "fuck my life mondays". It is a negative feeling/mood at the start of the start of the school/work week, typically caused by exhaustion and dread of the labour to come. The term is similar to having a "case of the mondays" and opposite to the term TGIF "thank god its friday"

Its monday morning, the coffee machine is broke, your boss is on your case and your extremely exhausted from the weekend. fmlm.